S-290 Final Exams with 100% Correct Verified Answers 2024/2025, Exams of Social Sciences

Download S-290 Final Exams with 100% Correct Verified Answers 2024/2025 and more Exams Social Sciences in PDF only on Docsity! S-290 Final Exams with 100% Correct verified Answers 2024/2025 T/F Topography can directly and indirectly affect fuels and their availability for combustion. True Of the three primary environmental factors that influence fire behavior, which is the least variable? Topography The least critical form of heat transfer that influences rate of spread in a running wild land fire is: Conduction The point to which a combustible material must be heated to produce self-sustaining combustion is known as the: Ignition temperature Fireline intensity is dependent upon: All of the above. Fuel size Fuel moisture Fuel temperature Fuel compactness and arrangement T/F Two requirements for long range spotting are wind and a well developed convection column. True A fire that advances through canopies of brush and trees is known as a: Crown fire Fire is burning in litter on top of the ground, but occasionally carries into the crowns of individual trees, which produces burning embers that start new fires outside the fire perimeter. Surface fire with torching and spotting. Fire begins burning into the crowns and spreads through the canopy. There is a sudden increase in fireline intensity where the fire controls it's environment. At one point flames can be seen carried high into the convection column with a whirling motion. Ground fire with smoldering and flare ups. T/F Upward moving air contracts and warms. False As air sinks, it. What is the general effect of stable air on wild land fires? Fire activity decreases What conditions will occur under a surface inversion during the morning hours? All of the above Temperatures are cool, winds are calm or light Fire activity is decreased Pollutants can accumulate under inversions What are the different lighting processes that can lead to thunderstorm development? Frontal, orographic, thermal, convergence T/F Unstable air can often be found in low pressure systems and on the leading edge of cold fronts. True T/F Unstable air can be formed by either heating the air near the ground or by cooling the air aloft. True Wind direction is: The direction the wind is blowing from. A wind is caused by: The direction the wind is blowing from. A slope wind is caused by: Warm air rising and cold air settling. Foehn winds can adversely affect wild land fires because they can produce: Strong winds, warmer temperatures, and very low RH. When stable air is forced over a mountain range, and then descends the leeward slopes as dry, warmed air, it is called: A foehn wind T/F Bends in canyons are likely places for wind eddies to form. True Local winds are best defined as: Small scale convective winds of local origin caused by differences in heating and cooling. East, Mono, Santa Ana, and Chinook are all examples of: Foehn winds T/F Air flows clockwise around low pressure systems and counterclockwise around high pressure systems. False Slope affects fuel availability to burn because: Fuels are preheated upslope through radiation and convection. Rolling firebrands ignite new fuels below. Select the correct statement regarding the shape of the country and it's effect on wild land fire behavior. Which fuel has the higher surface-area-to-volume ration? Grass The 1 hour timelag fuel category is: 0.0 to 1/4 inch in diameter Fuel moisture timelag can best be described as: The rate at which dead fuel gains or loses moisture. 1 hour timelag fuel moisture is used in fire behavior calculations to determine: Whether fine dead fuels are available for ignition and fire spread. The five stages of vegetative development for live fuel moisture are: 300%, 200%, 100%, 50%, less 30% The following statement best describes timelag fuel categories: 1 hour timelag fuels react to changes in RH mush faster than 100 hour fuels. T/F Foehn winds always cause fuels to gain in moisture content. False T/F Dead grass reacts like a 1 hour timelag fuel. True The fuel moisture at which fire will not spread is the: Moisture of extinction Inputs used to determine fine dead fuel moisture content are: Time of day, month of year, dry bulb temperature, RH, aspect, percent slope, shading of surface fuels. Select the fuel complex that would reach it's moisture of extinction first during nighttime humidity recovery. Cured cheatgrass If the wet build is not read at it's lowest point, what will happen? The calculated RH will be too high. What weather processes can and should be monitored visually? All of the above Thunderstorm buildups Clouds Approaching cold fronts Indications of a stable or unstable air When a cold front or thunderstorms are forecast in the vicinity of a fire, what is the most important information a security weather watch can provide? Strong shifting winds The criteria for determining a Red Flag Warning is a combination of high to extreme fire danger and a critical fire weather pattern such as: All of the above Dry lightning Lightning following an extremely dry period Unusually low RH Very dry and unstable air Expect moderate to long range spotting downwind. Strong winds aloft could surface on the fire. Wild land fire behavior in the third dimension: All of the above Presents a vertical dimension to fire suppression Exhibits crowning, spotting, and vortex phenomena. May affect the atmosphere near the fire. 4 factors that are responsible for the occurrence of fire behavior in the third dimension are: Available fuels, wind, low atmospheric moisture, and instability. Three stages of crown fire development are: Passive, active, and independent. T/F Crown fire development depends on crown flammability along with adequate surface-to-crown and crown-to-crown heat transfer. True The factors that contribute to the spotting problem can be classified into three general areas: Firebrand source, transportation, and the receiving fuel. Probability of ignition is determined by: Fuel shading, fine dead fuel moisture percent, and dry bulb temperature. T/F Vortices are grouped as vertical or horizontal depending on their axis of rotation. True When the wild land fire environment is dominated by a ______ fire, the convection column overpowers the wind field. Plume-dominated T/F Continous fine fuels, heavy fuel loadings, ladder fuels, crown spacing, and special fuel situations are fuel characteristics that should NOT be monitored. False Low RH and a high 1000 hour timelag fuel moisture are both critical fuel moisture indicators that should be monitored. False T/F Steep slopes, chutes, saddles, and narrow canyons are terrain indicators that should be monitored. True T/F Strong surface winds, lenticular clouds, high fast moving clouds, approaching cold front, cumulonimbus development, and sudden calm or battling winds are all indicators of wind that are not of great concern to wild land firefighters. False Which of the following is an indicator of stable air? Inversion Which is an indicator of possible fire behavior problems? All of the above Leaning, sheared, or well-developed smoke column Trees crowning